USA, New Zealand.
That's it.
The advertising amount and impact in NZ is a lot lower than in the US as our healthcare system is largely public (government funded) with a single buyer (Pharmac) of pharmaceuticals that exercises considerable pricing power, and is unafraid to change brands. Most of us go to the doctor and take what is prescribed.
https://www.asa.co.nz/codes/codes/therapeutic-and-health-adv...
For example, I loath that they advertise paracetamol (acetaminophen) as "better for the stomach" directly targeting Aspirin and other NSAIDS. No mention of how many peoples livers get permanently fucked by paracetamol.
Unfortunately the advertising propaganda is successful, and people avoid safe drugs that have side effects that can be managed. Evil.
This is already the case in many places outside the USA (Canada, Europe, Brazil, Hong Kong).
https://en.wikipedia.org/wiki/Direct-to-consumer_advertising